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Nanotech Grows Up

If sober acknowledgement of a technology's potential shortcomings can be taken as a sign of impending maturity, then nanotechnology took a giant step toward commercial adulthood at the Commercialization of NanoMaterials 2006 conference in Pittsburgh in September. In the short span between the last conference, in April of 2005 and this one, the conversational buzz shifted from verbal contests about just what nanotechnology is to the need for environmental, health and safety standards for particles that are sufficiently small to escape both detection by the human visual system and the filtering mechanisms of the human respiratory system.

At the conference, more than 250 movers and shakers from enterprises ranging from highly capitalized multinational corporations to barely funded startups exchanged ideas with government regulators and academic researchers about strategies and tactics for transforming the exotic properties of nanoscale materials into valuable products for consumers.  It is perhaps ironic that those same exotic properties that initiated nanotech's ascent to the position of fair-haired child of advanced technology are at the same time viewed as potential liabilities for companies that attempt to exploit them. While on the ideal side of the picture, nanotechnology has spawned innumerable bright ideas in laboratories around the world, on the pragmatic side it has also spawned as many if not more concerns about the unforeseeable impacts of releasing upon the world a new set of materials that have come into being mainly due to their novel properties.

Whether nanotech's downside potential is real or imagined, it is accursed by a lineage of infamous forebears, including asbestos, diesel exhaust particulates and perfluorooctanoic acid (PFOA). Combine this rogue's gallery of ancestors with a more recent family tree populated by unimagined size-dependent physical properties and increased reactivity, and nanotech's dream has the potential to morph abruptly into a nightmare. With EPA regulations setting alarms for diesel exhaust particles smaller than 2.5 micrometers (2,500 nanometers), the regulatory prospects for particles one thousand times as small would appear to be dim. However, government calls for collaboration with all parties, along with industry calls for such cautionary measures as treating all nanoscale waste materials as hazardous, and appeals for corporate stewardship of the environment cast a promising light on what may have been a foreboding picture.

Fortunately, we know quite a lot about how bulk scale materials behave and where nanoparticles accumulate in the human body. Unfortunately, we know almost nothing about how the human body copes with nanoscale particles once they accumulate. For example, the question of whether nanoparticle toxicity is attributable to morphological structure, chemical reactivity or simple particle size remains, as yet, unanswered. Neither do we know whether the cell’s excretory mechanism is adequate for the elimination of alien nanoparticles. We do know, however, that particles ranging between about one-tenth of a nanometer and twenty-five nanometers tend to accumulate in air passages in the head, trachea and lung. We also know that the alveolar sacs, where oxygen and carbon dioxide are swapped in our lungs, tend to get more than their fair share of particles, especially in the smaller range. To exacerbate the specter of tiny particles clogging up our respiratory systems, the alveolar sacs also engage in the elimination of water vapor from our lungs, which injects the issues of hydrophilicity/phobicity/solubility, atmospheric pressures and concentration gradients into an already complex equation. While these issues are routinely managed at bulk scale, they are cause for concern at nanoscale because we do not know all of the behavior characteristics of nanoscale materials. What is more, because biological systems tend to be systemically complex and mathematically elusive, the limits of our knowledge tend to shift the nature of the problem from one of scientific complexity to one of vague uncertainty.

In short, the imbalance between what we do and don't know about all things nano is tempered only by the notion that nobody knows enough to make risk-free decisions on either side of the equation. As such, calls for collaboration and cooperation in the creation of cautious best practices and standards are widespread among virtually all players.

In a panel discussion by business and government thought-leaders, the need for more knowledge pervaded the conversation. The broad consensus was to err on the side of caution and conservancy at all stages of research, development and production of nanomaterials; to bear in mind that the purpose of any nanotechnology endeavor should be the improvement of the human condition; and that since planet Earth is the place we will live for the foreseeable future, it is incumbent upon science and technology to protect it. 

Sounds like a sensible approach for dealing with a growing youngster of any sort.

This story first appeared on The Minerals Metals and Materials Society web site.

©Copyright 2007 Thomas P. Imerito/ dba Science Communications

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